GSM VS. CDMA Why You Should Know The Difference CDMA or GSM refers to the type of network technology the phone uses. Some carriers use CDMA and some use GSM. Your choice of carrier and the technology it uses for its network might make the difference between being productive and connected or ending up with no signal. It’s probably the understatement of the decade to say that cell phones have become the single greatest tool in business. In today’s world the ability to communicate with business associates while on the go is not just an advantage, it’s a necessity.
And because of that, the choices people make when choosing their handheld devices matter more than ever. When it comes time to select a cell phone or smart phone, the major part of the evaluation people make focuses on the features and benefits of the handset. People may choose a device with the best features but in other way they spend money as few as possible. A device with features such as access to the Internet and email, an organizer that will sync with Outlook will be selected. This features can take the owner scheduler, contacts, and information on the road.
And most importantly, the body and size of the phone cell, the slick one is better. But if people conduct a lot of their business on the road or internationally, the most important decision they make regarding their service may not have anything at all to do with the features they usually consider important for handhelds. They choice of carrier and the technology it uses for its network might make the difference between being productive or ending up out of area. By now, people have probably heard all of the acronyms in the alphabet soup of carrier technologies.
The two major terms that pertain to cellular phone communication that people are likely to run into GSM and CDMA, the two major technologies service providers use to carry voice signals across the network. But what are they and why do they matter? There are our focuses now, so in this paper we will reveal some things in other to make clear the problem about this case, such as: Here are two major methods for wireless communication. They are CDMA (Code Division Multiple Access) and GSM (Global System for Mobile Communications).
Those two methods, which have different protocol and standards, have different process for providing wireless communication. How those two methods exactly work? Those different processes explained above, will lead to the difference of their advantages. Futhermore, current-marketing-scope of those two methods will differ their advantages too. What are advantages and disadvantages of those two methods? Those two methods have the same business action. Futhermore, those methods may exploit the same network coverage too. Hence, how far exactly those two methods interferes each other?
GSM (Global System for Mobile communications, originally from Groupe Special Mobile) is the most popular standard for mobile phones in the world, with its promoter, the GSM Association, estimating that the GSM service provides 82% of the global mobile market and is used by over 2 billion people across more than 212 countries and territories. Code division multiple access (CDMA) describes a communication channel access principle that employs spread-spectrum technology and a special coding scheme (where each transmitter is assigned a code).
CDMA also refers to digital cellular telephony systems that use this multiple access scheme, as pioneered by QUALCOMM, and W-CDMA by the International Telecommunication Union (ITU), which is used in GSM’s UMTS. Whereas Global System for Mobile Communications (GSM) is a specification of an entire network infrastructure, CDMA relates only to the air interface — the radio portion of the technology. For example, GSM specifies an infrastructure based on internationally approved standard, while CDMA allows each operator to provide network features it finds suitable.
On the air interface, the signalling suite (GSM: ISDN SS7) work has been progressing to harmonise these features GSM (Global System for Mobile Communications). GSM is the “branded” term referring to a particular use of TDMA (Time-Division Multiple Access) technology. GSM is the dominant technology used around the globe and is available in more than 100 countries. It is the standard for communication for most of Asia and Europe. GSM operates on four separate frequencies: You’ll find the 900MHz and 1,800MHz bands in Europe and Asia and the 850MHz and 1,900MHz (sometimes referred to as 1. GHz) bands in North America and Latin America. GSM allows for eight simultaneous calls on the same radio frequency and uses “narrowband” TDMA, the technology that enables digital transmissions between a mobile phone and a base station. With TDMA the frequency band is divided into multiple channels which are then stacked together into a single stream, hence the term narrowband. This technology allows several callers to share the same channel at the same time. CDMA (Code Division Multiple Access). CDMA takes an entirely different approach from GSM/TDMA. CDMA spreads data out over the channel after the channel is digitized.
Multiple calls can then be overlaid on top of one another across the entire channel, with each assigned its own “sequence code” to keep the signal distinct. CDMA offers more efficient use of an analog transmission because it allows greater frequency reuse, as well as increasing battery life, improving the rate of dropped calls, and offering far greater security than GSM/TDMA. For this reason CDMA has strong support from experts who favor widespread development of CDMA networks across the globe. Currently, you will find CDMA mostly in the United States, Canada, and North and South Korea. As an interesting aside, CDMA was actually invented for the military during World War II for field communications. ) (Can you spell propaganda? ) Data transfer methods GSM’s high-speed wireless data technology, GPRS (General Packet Radio Service), usually offers a slower data bandwidth for wireless data connection than CDMA’s high-speed technology (1xRTT, short for single carrier radio transmission technology), which has the capability of providing ISDN (Integrated Services Digital Network)-like speeds of as much as 144Kbps (kilobits per second).
However, 1xRTT requires a dedicated connection to the network for use, whereas GPRS sends in packets, which means that data calls made on a GSM handset don’t block out voice calls like they do on CDMA phones. Note: The new GSM EDGE technology means that GSM speeds have caught up with CDMA, but EDGE coverage and availability remains patchy. Subscriber Identity Module (SIM Card) The most obvious distinction between GSM and CDMA is the SIM (subscriber identity module) card, the onboard memory device in a GSM phone that identifies a user and stores their information.
You can swap GSM SIM cards between phones which enables you to move all of your contact and calendar information over to a new handset with no hassle. [pic][pic][pic][pic][pic][pic][pic]CDMA operators answer this flexibility with their own service that stores user data on the operator’s database. This service makes it possible to swap handsets with little trouble and also provides the ability to recover contact data even if their phone is lost or stolen. These services are usually available for GSM phones too, so it’s not really an advantage of CDMA, more of a disadvantage is that they don’t have SIM cards.
DIFFERENCE BETWEEN GSM AND CDMA The major difference between GSM/TDMA and CDMA is in the way they divide up those signals between multiple users. GSM/TDMA uses a Time Division method. TDMA, in fact, stands for Time Division Multiple Access. Simply put, this means that each device on the local network is allocated a time slice where it “owns” the bandwidth, and it can send/receive its data. So lets just pick a number and say there are 30 available time slices in a given cycle. Each phone would then get 1/30th of every cycle that it could send and receive data (aka, voice).
CDMA uses a different method, called Code Division Multiple Access. The specifics of how it breaks the cycle up are beyond me, but how it works out is that the phones only get a slice of the bandwidth cycle when they actually need one. So if you are not talking, and the other person is not talking, nothing is transmitted. With GSM/TDMA, each phone is transmitting and receiving during its slices of the bandwidth cycle, whether it needs it or not. Since most conversations are comprised largely of silence, the end result is that CDMA phones have to transmit less data.
They don’t have to send silence, like GSM/TDMA phones do. This means a few things. More CDMA calls can be fit into a given amount of frequency spectrum (ie. it is more efficient for the network), less radiation is being created from the phone towards the user (you only get radiation when you are talking, basically), and battery power is conserved since the handset only transmits when it actually has something to send. There are other differences, too, that I can’t get into. For one, it is harder to implement a CDMA network. The tower placement is more difficult.
Dealing with hills is more difficult than with GSM/TDMA. Things like that. But in general, CDMA is vastly superior technology. Not surprising since Qualcomm’s version of it (that which is used in CDMA and WCDMA phones) is newer technology, even if the basics were in use by the US military as far back as the 40s. The important thing for me, though, is the SIM card. Had CDMA implemented the use of a SIM card (something it very easily could have done), then the North American market would be very different today, and there would be more CDMA networks in other countries.
The SIM card allows people to easily switch phones, and that helps the market. How Does Speed Differentiate GSM and CDMA Today, cell phones are used for much more than making a call or sending a text message. Phones are used for live video streaming, downloads and these services depend heavily on the speed provided by the carriers. Until very recently, CDMA was considered faster because of the provision of a full frequency spectrum to every channel but GSM too, like CDMA, has offered 3G services to its subscribers with the help of WCDMA technology.
EVDO, also known as CDMA2000, is CDMA’s answer to the need for speed with a downstream rate of about 2 megabits per second, though some reports suggest real world speeds are closer to 300-700 kilobits per second (kbps). This is comparable to basic DSL. As of fall 2005, EVDO is in the process of being deployed. It is not available everywhere and requires a phone that is CDMA2000 ready. GSM’s answer is EDGE (Enhanced Data Rates for GSM Evolution), which boasts data rates of up to 384 kbps with real world speeds reported closer to 70-140 kbps.
With added technologies still in the works that include UMTS (Universal Mobile Telephone Standard) and HSDPA (High Speed Downlink Packet Access), speeds reportedly increase to about 275—380 kbps. This technology is also known as W-CDMA, but is incompatible with CDMA networks. An EDGE-ready phone is required. In the case of EVDO, theoretical high traffic can degrade speed and performance, while the EDGE network is more susceptible to interference. Both require being within close range of a cell to get the best speeds, while performance decreases with distance. International Use
Where international useage is important, GSM really does win hands down. GSM networks are used in more than 74% of the markets across the globe, and so users of tri-band or quad-band GSM handsets can travel to Europe, India, and most of Asia and still use their cell phones. CDMA offers no multiband capability and is rare outside of the United States so it is not really much use for international travellers. You can also move the SIM of a GSM-based phone to any other GSM-based phone, or use a different SIM in your own phone, making GSM the optimal choice for international travelers who need connectivity
Roaming: For the most part, both networks have fairly concentrated coverage in major cities and along major highways. GSM carriers, however, have roaming contracts with other GSM carriers, allowing wider coverage of more rural areas, generally speaking, often without roaming charges to the customer. CDMA networks may not cover rural areas as well as GSM carriers, and though they may contract with GSM cells for roaming in more rural areas, the charge to the customer will generally be significantly higher. International Roaming: If you need to make calls to other countries, a GSM arrier can offer international roaming, as GSM networks dominate the world market. If you travel to other countries you can even use your GSM cell phone abroad, providing it is a quad-band phone (850/900/1800/1900 MHz). By purchasing a SIM card with minutes and a local number in the country you are visiting, you can make calls against the card to save yourself international roaming charges from your carrier back home. CDMA phones that are not card-enabled do not have this capability, however there are several countries that use CDMA networks. Check with your CDMA provider for your specific requirements.
According CDG. org, CDMA networks support over 270 million subscribers worldwide, while GSM. org tallies up their score at over 1 billion. As CDMA phones become R-UIM enabled and roaming contracts between networks improve, integration of the standards might eventually make differences all but transparent to the consumer. The chief GSM carriers in the United States are Cingular Wireless, recently merged with AT&T Wireless, and T-Mobile USA. Major CDMA carriers are Sprint PCS, Verizon and Virgin Mobile. There are also several smaller cellular companies on both networks